I. Field of the Invention
The present invention pertains generally to the field of communications, and more specifically to methods and apparatus for channel optimization during point-to-point protocol (PPP) session requests.
II. Background
With the increasing popularity of both wireless communications and Internet applications, a market has arisen for products and services that combine the two. As a result, various methods and systems are under development to provide wireless Internet services that would allow a user of a wireless telephone or terminal to access email, web pages, and other network resources. Because information on the Internet is organized into discrete “packets” of data, these services are often referred to as “packet data services.”
Among the different types of wireless communication systems to be used to provide wireless packet data services are code division multiple access (CDMA) systems. The use of CDMA modulation techniques is one of several techniques for facilitating communications in which a large number of system users are present. The framing and transmission of Internet Protocol (IP) data through a CDMA wireless network is well known in the art and has been described in TIA/EIA/IS-707-A, entitled “DATA SERVICE OPTIONS FOR SPREAD SPECTRUM SYSTEMS,” hereinafter referred to as IS-707.
Other multiple access communication system techniques, such as time division multiple access (TDMA), frequency division multiple access (FDMA), and AM modulation schemes such as amplitude companded single sideband (ACSSB) modulation are known in the art. These techniques have been standardized to facilitate interoperation between equipment manufactured by different companies. CDMA communications systems have been standardized in the United States in Telecommunications Industry Association TIA/EIA/IS-95-B, entitled “MOBILE STATION-BASE STATION COMPATIBILITY STANDARD FOR DUAL-MODE WIDEBAND SPREAD SPECTRUM CELLULAR SYSTEMS,” hereinafter referred to as IS-95.
The International Telecommunications Union recently requested the submission of proposed methods for providing high-rate data and high-quality speech services over wireless communication channels. A first of these proposals was issued by the Telecommunications Industry Association, entitled “The cdma2000 ITU-R RTT Candidate Submission,” and hereinafter referred to as cdma2000. A second of these proposals was issued by the European Telecommunications Standards Institute (ETSI), entitled “The ETSI UMTS Terrestrial Radio Access (UTRA) ITU-R RTT Candidate Submission,” also known as “wideband CDMA,” and hereinafter referred to as W-CDMA. A third proposal was submitted by U.S. TG 8/1, entitled “The UWC-136 Candidate Submission,” hereinafter referred to as EDGE. The contents of these submissions are public record and are well known in the art.
Several standards have been developed by the Internet Engineering Task Force (IETF) to facilitate mobile packet data services using the Internet. Mobile IP is one such standard, and was designed to allow a device having an IP address to exchange data with the Internet while physically travelling throughout a network (or networks). Mobile IP is described in detail in IETF request for comments (RFC), entitled “IP Mobility Support,” and incorporated by reference.
Several other IETF standards set forth techniques referred to in the above-named references. Point-to-Point Protocol (PPP) is well known in the art and is described in IETF RFC 1661, entitled “The Point-to-Point Protocol (PPP)” and published in July 1994, hereinafter referred to as PPP. PPP includes a Link Control Protocol (LCP) and several Network Control Protocols (NCP) used for establishing and configuring different network-layer protocols over a PPP link. One such NCP is the Internet Protocol Control Protocol (IPCP), well known in the art and described in IETF RFC 1332, entitled “The PPP Internet Protocol Control Protocol (IPCP),” published in May of 1992, and hereinafter referred to as IPCP. Extensions to the LCP are well known in the art and described in IETF RFC 1570, entitled “PPP LCP Extensions,” published in January 1994, and hereinafter referred to as LCP.
Mobile stations, such as, e.g., cellular or PCS telephones with Internet connections, typically transmit packet data over a network by establishing a PPP connection (or PPP instance, or PPP session), with a packet data service node (PDSN). The mobile station sends packets across an RF interface such as, e.g., a CDMA interface, to a base station or packet control function. The base station or packet control function establishes the PPP instance with the PDSN. More than one such PPP instance may be established contemporaneously (e.g., if a phone and a laptop each require a connection). Data packets are routed from a foreign agent (FA) of the PDSN to a home agent (HA) via an IP network in accordance with the particular PPP instance. Packets being sent to the mobile station are routed from the HA via the IP network to the FA of the PDSN, from the FA of the PDSN to the base station or packet control function via the PPP instance, and from the base station or packet control function to the mobile station via the RF interface.
When a mobile station leaves the vicinity of a PDSN and enters the vicinity of another PDSN, the mobile station sends an origination message. If the mobile station is engaged in a data call, the origination message requests reconnection or establishment of the associated PPP instance. Otherwise, the origination message informs the new PDSN of the new location of the mobile station. Nevertheless, any data packets being sent to the mobile station will be routed to the old PDSN because the mobile station does not have a PPP instance established with the new PDSN. Accordingly, packets destined for the mobile station will become lost. Thus, there is a need for a method of informing a PDSN of the number and identities of PPP instances to be established for a newly arriving mobile station. There is also a need for a method of informing a PDSN of the number and identities of PPP instances to optimize the usage of Air Interface and radio access network (RAN) PDSN interface (RPI) communications channel resources.